Liquid Guardians: Biomolecular Condensates Shield Heterochromatin Against Cellular Senescence

Heterochromatin, a crucial constituent of the eukaryotic nucleus with highly conserved and transcriptionally silenced characteristics, plays a pivotal role in safeguarding genome stability, regulating nuclear morphology, and mediating cell fate. Recent convincing evidence indicates that the formation and maintenance of heterochromatin are implicated in cellular senescence and age-associated disorders. Interestingly, an attractive mechanism involving liquid-liquid phase separation (LLPS) may exert a central role in regulating heterochromatin formation and maintenance. In this review, we provide an overview of recent research to illustrate the role and regulatory mechanism of the biomolecular condensates in the regulation of heterochromatin stabilization. In addition, we elucidate how heterochromatin loss contributes to cellular senescence by triggering genome instability, and explore the potential therapeutic strategies to counteract cellular senescence and age-related pathologies by restoring heterochromatin stability. Finally, we outline current research challenges and future directions aimed at achieving a more comprehensive understanding of the link among heterochromatin regulation, phase separation, and cellular senescence, for ameliorating the effects of ageing in the future.